1. Field of the Invention
The present invention relates generally to conveyor systems and more particularly, to a closed loop conveyor system including a pair of grooved pulleys and a conveyor belt with longitudinal ribs formed to mate with the grooves to provide a locking engagement between the belt and the pulleys.
2. Description of the Prior Art
Heretofore, endless belts used in closed loop conveyor systems have usually had smooth interior pulley-engaging surfaces and the pulleys used to drive these belts have had smooth driving surfaces which were crowned to maintain the belt centered over the pulley. In cases where off-centered loads are carried by the belt, or where the belts are side loaded, it is not unusual to have cross tensions build up in the belt which are substantial enough to overcome the centering action of the pulley crowns and cause the belt to be thrown off the pulleys.
In an attempt to provide improved centering of the belt over the pulley, V-belt systems have been used. In a V-belt system a rib which is V-shaped in cross section is bonded to the interior surface of the conveyor belt and a corresponding V-shaped groove is formed in the pulley surfaces for receiving the rib as it passes over the pulleys. However, ribs of this configuration still tend to jump out of the groove. When this occurs, the bond between the rib and the carcass generally begins to tear apart. Thus, belts having V-shaped ribs tend to have a reduced useful life.